The mission of the Mass Spectrometry Core (Core A) is to provide cost-effective, state-of-the-art instrumentation and analytical expertise to investigators in the Research Center for Pharmacology and Drug Toxicology. The MS Core has ten mass spectrometers available for general use, including five triple quadrupole LC/MS instruments and two GC/MS instruments. Funds are requested in the budget to 50% cost-share the purchase of a new generation triple quadrupole LC/MS instrument to replace one of the obsolete current instruments to further enhance low level quantitation of target analytes. Five projects will participate in this Research Center and the Core will be used by each of them. The primary use of the Core will be for identification and characterization of small molecule metabolites in physiologic fluids and quantitation of eicosanoids, prostaglandins and oxidized lipids by isotope dilution mass spectrometry. Core personnel actively participate in the research goals of this center and will undertake short projects, such as those to enhance chromatographic techniques and instrument sensitivity and to explore derivatization chemistry to enhance the ionization properties of target compounds. The Core will be managed by Dr. Richard Caprioli, Professor of Biochemistry in conjunction with Dr. David L. Hachey, Professor of Pharmacology and Biochemistry, and routine duties of the core will be done by four full-time laboratory personnel and an administrative assistant. Laboratory personnel assist users in developing analytical methods, designing experiments, developing standard operating procedures, maintaining quality control records of instrument performance and maintenance history, performing routine assays for investigators and training students and fellows in the theoretical and practical aspects of MS. The core has a regular training program given six times per year in which it offers new users specialized training in instrument operation and sample preparation. Furthermore, the center investigators will have access to more advanced instrumentation in the MS Research Center, and these will be made available to investigators through arrangements with Dr. Caprioli as needs dictate. Thus, the Core satisfies the routine analytical needs of center investigators and assures that new analytical capabilities will be available to meet more demanding research challenges that fall beyond the scope of a routine service core.